Gas burner assembly for a cooktop appliance

ABSTRACT

A gas burner assembly for a cooktop appliance and a method for operating the same are provided. The gas burner assembly includes a primary burner, a boost burner, a solenoid valve for regulating a flow of boost fuel to a boost burner chamber, and a forced air supply source for selectively urging a flow of air into the boost burner chamber. The method includes activating the boost burner only after determining that the primary burner is ignited. Activating the boost burner may include activating the forced air supply source and opening the solenoid valve only after a delay period measured from the activation of the forced air supply source. In addition, the method may further comprise deactivating the forced air supply source to stop the flow of air to the boost burner chamber only after a purge delay period measured from the closing of the solenoid valve.

FIELD OF THE INVENTION

The present subject matter relates generally to cooktop appliances and more particularly to gas burner assemblies for cooktop appliances and their methods of operation.

BACKGROUND OF THE INVENTION

Gas burners are commonly used on the cooktops of household gas cooking appliances including e.g., range ovens and cooktops built into cabinetry. For example, gas cooktops traditionally have at least one gas burner positioned at a cooktop surface for use in heating or cooking an object, such as a cooking utensil and its contents. Control knobs are typically used to adjust the power level of the heating element, e.g., the amount of fuel directed to the burner, and thus the amount of heat delivered by the gas burner.

Normally aspirated gas burners rely on the energy available in the form of pressure from the fuel supplied to the gas burner to entrain air for combustion. Because the nominal pressure in households is relatively low, there is a practical limit to the amount of primary air a normally aspirated gas burner can entrain. Introducing a fan or another forced air supply into a gas burner assembly may improve the mixture of fuel and air for improved operation at higher outputs, with shorter flames and improved combustion, and with improved efficiency.

Notably, conventional forced air gas burners may experience several operability issued during transient operation, i.e., during ignition and shut off. For example, forced air burners often use mixing chambers having large volumes to increase the mixing and residence time between the fuel and air to achieve a homogeneous fuel mixture. However, when the burner is shut off, a large volume of residual fuel mixture in the mixing chamber will burn off as long-reaching yellow flames. In addition, during ignition, because the forced air supply (e.g., the fan) has a relatively slow ramp up time, the initial fuel mixture in the chamber may be fuel-rich. In addition, fan boosted burners can discharge a large volume of fuel when turned on if ignition is unsuccessful or delayed.

Accordingly, an improved gas burner assembly is desirable. More particularly, a fan boosted gas burner assembly that minimizes the amount of fuel released prior to ignition and ensures that long flames are not generated when the burner is turned on or off would be particularly beneficial.

BRIEF DESCRIPTION OF THE INVENTION

The present disclosure relates generally to a gas burner assembly for a cooktop appliance and a method for operating the same. The gas burner assembly includes a primary burner, a boost burner, a solenoid valve for regulating a flow of boost fuel to a boost burner chamber, and a forced air supply source for selectively urging a flow of air into the boost burner chamber. The method includes activating the boost burner only after determining that the primary burner is ignited. Activating the boost burner may include activating the forced air supply source and opening the solenoid valve only after a delay period measured from the activation of the forced air supply source. In addition, the method may further comprise deactivating the forced air supply source to stop the flow of air to the boost burner chamber only after a purge delay period measured from the closing of the solenoid valve. Additional aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.

In one exemplary embodiment, a gas burner assembly for a cooktop appliance is provided. The gas burner assembly includes a primary burner including a plurality of primary flame ports in fluid communication with a primary burner chamber for receiving a flow of primary fuel and a boost burner including a plurality of boost burner ports in fluid communication with a boost burner chamber for receiving a flow of boost fuel. A solenoid valve regulates the flow of boost fuel to the boost burner chamber and a forced air supply source selectively urges a flow of air into the boost burner chamber. A controller is operably coupled to the solenoid valve and the forced air supply and is configured for receiving a command to ignite the boost burner, determining that the primary burner is ignited, and activating the boost burner after determining that the primary burner is ignited.

In another exemplary embodiment, a method for operating a gas burner assembly is provided. The gas burner assembly includes a primary burner positioned concentrically below a boost burner, a solenoid valve for regulating a flow of boost fuel to a boost burner chamber, and a forced air supply source for selectively urging a flow of air into the boost burner chamber. The method includes receiving a command to ignite the boost burner, determining that the primary burner is ignited, and activating the boost burner after determining that the primary burner is ignited.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

FIG. 1 provides a top view of a cooktop appliance according to an exemplary embodiment of the present subject matter.

FIG. 2 provides a perspective view of a gas burner assembly of the exemplary cooktop appliance of FIG. 1 according to an exemplary embodiment of the present subject matter.

FIG. 3 provides a bottom perspective view of the exemplary gas burner assembly of FIG. 2 positioned within a top panel of the exemplary cooktop appliance of FIG. 1.

FIG. 4 provides an exploded perspective view of the exemplary gas burner assembly of FIG. 2.

FIG. 5 provides a cross sectional view of the exemplary gas burner assembly of FIG. 2.

FIG. 6 provides a top perspective view of a bottom housing of the exemplary gas burner assembly of FIG. 2 with fuel and air inlets illustrated in phantom.

FIG. 7 provides a bottom perspective view of a center body of the exemplary gas burner assembly of FIG. 2.

FIG. 8 provides a cross sectional view of the exemplary center body of FIG. 7.

FIG. 9 provides another cross sectional view of the exemplary center body of FIG. 7.

FIG. 10 provides a cross sectional view of the exemplary gas burner assembly of FIG. 2 with an exemplary flow path of fuel and air illustrated by dotted lines and portions of gas burner assembly removed for clarity.

FIG. 11 is a schematic view of a gas burner assembly and a gaseous fuel supply circuit according to an example embodiment of the present subject matter.

FIG. 12 is an operating schematic of a gas burner assembly according to an example embodiment of the present subject matter.

FIG. 13 is another operating schematic of a gas burner assembly according to an example embodiment of the present subject matter.

FIG. 14 is a method of operating a gas burner assembly according to an exemplary embodiment of the present subject matter.

Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

The present disclosure relates generally to a gas burner assembly for a cooktop appliance 100. Although cooktop appliance 100 is used below for the purpose of explaining the details of the present subject matter, one skilled in the art will appreciate that the present subject matter may apply to any other suitable consumer or commercial appliance. For example, the exemplary gas burner assemblies described below may be used on other types of cooking appliances, such as ranges or oven appliances. Cooktop appliance 100 is used in the discussion below only for the purpose of explanation, and such use is not intended to limit the scope of the present disclosure in any manner.

FIG. 1 illustrates an exemplary embodiment of a cooktop appliance 100 of the present disclosure. Cooktop appliance 100 may be, e.g., fitted integrally with a surface of a kitchen counter, may be configured as a slide-in cooktop unit, or may be a part of a free-standing range cooking appliance. Cooktop appliance 100 includes a top panel 102 that includes one or more heating sources, such as heating elements 104 for use in, e.g., heating or cooking. Top panel 102, as used herein, refers to any upper surface of cooktop appliance 100 on which utensils may be heated and therefore food cooked. In general, top panel 102 may be constructed of any suitably rigid and heat resistant material capable of supporting heating elements 104, cooking utensils, and/or other components of cooktop appliance 100. By way of example, top panel 102 may be constructed of enameled steel, stainless steel, glass, ceramics, and combinations thereof.

According to the illustrated exemplary embodiment, a user interface panel or control panel 106 is located within convenient reach of a user of cooktop appliance 100. For this exemplary embodiment, control panel 106 includes control knobs 108 that are each associated with one of heating elements 104. Control knobs 108 allow the user to activate each heating element 104 and regulate the amount of heat input each heating element 104 provides to a cooking utensil located thereon, as described in more detail below. Although cooktop appliance 100 is illustrated as including control knobs 108 for controlling heating elements 104, it should be understood that control knobs 108 and the configuration of cooktop appliance 100 shown in FIG. 1 is provided by way of example only. More specifically, control panel 106 may include various input components, such as one or more of a variety of touch-type controls, electrical, mechanical or electro-mechanical input devices including rotary dials, push buttons, and touch pads.

According to the illustrated embodiment, control knobs 108 are located within control panel 106 of cooktop appliance 100. However, it should be appreciated that this location is used only for the purpose of explanation, and that other locations and configurations of control panel 106 and control knobs 108 are possible and within the scope of the present subject matter. Indeed, according to alternative embodiments, control knobs 108 may instead be located directly on top panel 102 or elsewhere on cooktop appliance 100, e.g., on a backsplash, front bezel, or any other suitable surface of cooktop appliance 100. Control panel 106 may also be provided with one or more graphical display devices, such as a digital or analog display device designed to provide operational feedback to a user.

Operation of cooktop appliance 100 is controlled by a controller or processing device 110 (FIG. 1) that is operatively coupled to control panel 106 for user manipulation, e.g., to control the operation of heating elements 104. In response to user manipulation of control panel 106, controller 110 operates the various components of cooktop appliance 100 to execute selected instructions, commands, or other features.

Controller 110 may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with a cleaning cycle. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller 110 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software. Control panel 106 and other components of cooktop appliance 100 may be in communication with controller 110 via one or more signal lines or shared communication busses.

According to the illustrated embodiment, cooktop appliance 100 is a gas cooktop and heating elements 104 are gas burners, such as gas burner assembly 150 described below. As illustrated, heating elements 104 are positioned within top panel 102 and have various sizes, as shown in FIG. 1, so as to provide for the receipt of cooking utensils (i.e., pots, pans, etc.) of various sizes and configurations and to provide different heat inputs for such cooking utensils. In addition, cooktop appliance 100 may include one or more grates 112 configured to support a cooking utensil, such as a pot, pan, etc. In general, grates 112 include a plurality of elongated members 114, e.g., formed of cast metal, such as cast iron. The cooking utensil may be placed on the elongated members 114 of each grate 112 such that the cooking utensil rests on an upper surface of elongated members 114 during the cooking process. Heating elements 104 are positioned underneath the various grates 112 such that heating elements 104 provide thermal energy to cooking utensils above top panel 102 by combustion of fuel below the cooking utensils.

As shown schematically in FIGS. 1 through 3, cooktop appliance 100 includes a variety of control elements for regulating the amount of heat generated by heating elements 104. For example, as explained below, heating element 104 is a gas burner assembly 150 that uses one or more flows of fuel and one or more flows of air for combustion. Thus, cooktop appliance 100 includes fuel control valves 120 and fuel lines 122 for supplying a metered amount of fuel to heating element 104. Fuel lines 122 extend between control valves 120 and one or more fuel orifices of heating element 104. Thus, when control valves 120 are open, fuel such as propane or natural gas may flow through fuel lines 122 to the fuel orifices for combustion. Similarly, cooktop appliance 100 includes a forced air supply 124 and an air regulator 126 for controlling the amount of forced air introduced to heating element 104 for combustion. For example, forced air supply 124 may be a fan, an air compressor, or any other suitable source of air.

Cooktop appliance 100 may further include features for assisting mixing of air and fuel as the fuel enters heating element 104, e.g., injectors, Venturi mixers, etc. According to an exemplary embodiment, fuel control valves 120 are each coupled to a respective one of control knobs 108. Thus, a user may adjust fuel control valves 120 with control knobs 108, thereby regulating fuel flow to heating elements 104. Similarly, air regulator 126 may be either directly controlled by control knob 108 or may be controlled based on the amount of fuel supplied to obtain the desired air/fuel ratio for combustion. According to an exemplary embodiment, some or all of these control components may be mounted to panel top 102, e.g., on a bottom surface or underside of top panel 102.

Referring now generally to FIGS. 2 through 10, a gas burner assembly 150 that may be used with cooktop appliance 100 will be described in more detail. Although the discussion below refers to an exemplary gas burner assembly 150, it should be appreciated that the features and configurations described may be used for other heating elements in other cooking appliances or consumer appliances as well. For example, gas burner assembly 150 may be positioned elsewhere within cooktop appliance 100, may have different components or configurations, and use alternative mechanisms for mixing fuel and air for combustion. Other variations and modifications of the exemplary embodiment described below are possible, and such variations are contemplated as within the scope of the present subject matter.

Referring now to FIG. 4, an exploded view of gas burner assembly 150 will be described. As shown, gas burner assembly 150 generally defines an axial direction A, a radial direction R, and a circumferential direction C. As illustrated, gas burner assembly 150 is mounted within an aperture 152 defined in top panel 102 of cooktop appliance 100. More specifically, gas burner assembly 150 includes a bottom housing 154 that defines a bottom flange 156 and is generally positioned below top panel 102 and a center body 158 that defines a top flange 160 and is generally positioned above top panel 102. According to the illustrated embodiment, gas burner assembly 150 is installed in aperture 152 by joining bottom housing 154 and center body 158 using any suitable mechanical fastener 162, such as screws, bolts, rivets, etc. Similarly, glue, bonding, snap-fit mechanisms, interference-fit mechanisms, or any suitable combination thereof be used to join bottom housing 154 and center body 158.

Referring now also to FIG. 5, bottom housing 154 includes a bottom wall 164 and a side wall 166 which generally cylindrically shaped and defines an open top. In addition, center body 158 generally includes a cylindrical lower wall 168 that defines an inner chamber 170 and an upper wall 172 that extends along the radial direction R out to top flange 160. Center body 158 is mounted within bottom housing 154 such that it is positioned concentrically within bottom housing 154 to define an annular mixing chamber 174, e.g., positioned between lower wall 168 and cylindrical wall 166. In this manner, inner chamber 170 is positioned inward of mixing chamber 174 along the radial direction R to define two separate chambers. In addition, according to an exemplary embodiment, lower wall 168 of center body 158 defines a plurality of apertures 176 providing fluid communication between mixing chamber 174 and inner chamber 170.

Mixing chamber 174 and inner chamber 170 are generally configured for receiving a flow of air and a flow of fuel and fully premixing them into a homogenous fuel mixture prior to combustion. In this manner, for example, bottom housing 154 defines a boost fuel inlet 180 and a boost air inlet 182 that are each in fluid communication with mixing chamber 174. Boost fuel inlet 180 and boost air inlet 182 provide a flow of fuel and forced air, respectively, into mixing chamber 174. In order to increase residence time between the air and fuel to improve mixing, according to the illustrated embodiment, boost fuel inlet 180 and boost air inlet 182 are positioned proximate a top of mixing chamber 174, e.g., adjacent upper wall 172, and the plurality of apertures 176 are defined proximate a bottom of mixing chamber 174, e.g., as slots or openings defined by a distal end of lower wall 168. In this manner, fuel and air injected into mixing chamber 174 travels circumferentially within mixing chamber 174 around lower wall 168 as it migrates towards bottom wall 164 where it enters inner chamber 170 through apertures 176.

As best illustrated in FIG. 6, bottom housing 154 includes a variety of features to facilitate proper mixing of fuel and air for combustion. For example, boost fuel inlet 180 may terminate in a spray nozzle 183 (see FIGS. 4 and 5) for directing the flow of fuel as desired. In addition, as illustrated, boost fuel inlet 180 injects a flow of fuel along a first direction 184 and boost air inlet 182 injects a flow of air along a second direction 186. In order to generate turbulence between the two flows, second direction 186 is substantially perpendicular to first direction 184. More specifically, first direction 184 and second direction 186 define an intersection angle 188 of approximately 90 degrees. It should be appreciated that intersection angle 188 may vary according to alternative embodiments.

In addition, first direction 184 is substantially parallel to the axial direction A such that fuel is injected upward and second direction 186 extends tangentially from cylindrical wall 166 such that boost air inlet 182 discharges air tangentially. Moreover, boost fuel inlet 180 and boost air inlet 182 are illustrated as being positioned proximate to each other on bottom housing 154 such that the flow of air and fuel have high velocity when they begin mixing. The interaction between the two flows results in a desirable swirling motion within mixing chamber 174 (see FIG. 10) and results in high turbulence and extended residence time.

As best illustrated in FIG. 7, center body 158 also includes features to facilitate proper mixing of fuel and air for combustion. For example, as illustrated, apertures 176 extend through center body 158 at an angle 190 relative to the radial direction R. Angle 190 may be selected to reduce drag on the flow of fuel and air and/or to continue swirling the flows for improved mixing.

Referring again to FIGS. 4 and 5, cooktop appliance 100 further includes an upper housing assembly or upper housing 200 positioned over center body 158 along the axial direction A. Upper housing 200 may include one or more components for receiving and conditioning one or more flows of fuel and air and passing it to various flame ports defined by upper housing 200. As shown in the figures, upper housing 200 actually includes a top portion 202 and a bottom portion 204 that are joined together to define a primary burner and a boost burner, but these components will be referred to generally herein as upper housing 200.

Upper housing 200 generally defines a boost burner chamber 206 that extends along the axial direction A and is in fluid communication with inner chamber 170 of center body 158. As shown also in FIGS. 8 and 9, top portion 202 defines a plurality boost flame ports 210 spaced about the circumferential direction C and in fluid communication with boost burner chamber 206. In addition, a top cap 212 is positioned on top of top portion 202 to provide a clean appearance to gas burner assembly 150 and to help disperse the fuel mixture around boost flame ports 210.

Gas burner assembly 150 further includes a flow developer 220 for straightening the flow of fuel mixture prior to passing through boost flame ports 210. For example, as illustrated, top portion 202 defines flow developer 220 which is positioned between inner chamber 170 and boost burner chamber 206 for straightening or conditioning a flow of mixed fuel and air. It should be appreciated that although flow developer 220 is illustrated as being positioned at a bottom of upper housing 200, flow developer 220 could be defined by center body 158 or could be a separate component according to alternative embodiments. In general, flow developer 220 includes a plurality of conduits or passageways 222 that extend generally along the axial direction A between inner chamber 170 and boost burner chamber 206. According to alternative embodiments, flow developer 220 may include a plurality of fins extending along the axial direction A or any other flow straightening structure.

In addition to including a boost burner as described above, gas burner assembly 150 further includes a primary burner. According to an exemplary embodiment, the primary burner is a normally aspirated burner that may be regulated for normal operation while boost burner is a discretely operating (i.e., on or off) auxiliary forced air burner intended for performing high heat operation such as boiling a large pot of water. However, it should be appreciated that the primary burner and boost burner may both be incrementally regulated simultaneously or independently of each other according to alternative embodiments.

As shown, upper housing 200 defines a primary burner chamber 230, or more specifically, primary burner chamber 230 is defined between top portion 202 and bottom portion 204. A primary fuel inlet 232 is in fluid communication with primary burner chamber 230 for providing a flow of fuel into primary burner chamber 230. More specifically, as illustrated in FIGS. 4 through 7, primary fuel inlet 232 passes from bottom wall 164 of bottom housing 154 along the axial direction A through mixing chamber 174. Primary fuel inlet 232 then passes through an aperture 234 (FIG. 7) defined in upper wall 172 of center body 158 and terminates in a spray nozzle 236 within an air entrainment chamber 238 defined between upper wall 172 and bottom portion 204 of upper housing 200.

Air entrainment chamber 238 is in fluid communication with a primary air inlet 250 that extends about the circumferential direction C above top panel 102 of cooktop appliance 100. More specifically, primary air inlet 250 is defined between upper wall 172 of center body 158 and bottom portion 204 of upper housing 200. In this manner, fresh primary supply air may be drawn from ambient through primary air inlet 250 into air entrainment chamber 238. In addition, as best shown in FIG. 5, air entrainment chamber 238 is separated from primary burner chamber 230 by a divider wall 252 that extends along the radial direction R and is part of bottom portion 204. Divider wall 252 defines an aperture 254 (see FIG. 10) through which fuel discharged from spray nozzle 236 passes through air entrainment chamber 250 and into primary burner chamber 230. In this manner, ambient air from within air entrainment chamber 238 is entrained and mixed with the supply of fuel from primary fuel inlet 232 as it is injected into primary burner chamber 230.

In addition, a cylindrical channel 256 extends around aperture 254 and toward top portion 202 of upper housing 200. Notably, cylindrical channel 256 terminates proximate a top of primary burner chamber 230, e.g., adjacent top portion 202 of upper housing 200. In this manner, cylindrical channel 256 discharges a mixture of fuel and air proximate a top of primary burner chamber 230. In addition, top portion 202 of upper housing 200 defines a circumferential baffle 260 that is positioned within primary burner chamber 230 and extends down along the axial direction A toward bottom portion 204 to define an annular opening 262 proximate a bottom of primary burner chamber 230. In this manner, the fuel and air mixture that is ejected into primary burner chamber 230 migrates from a top of primary burner chamber 230 downward along the axial direction A toward annular opening 262, thereby increasing residence time and ensuring the mixture is more evenly dispersed throughout primary burner chamber 230 for improved combustion.

Upper housing 200 also defines a plurality of primary flame ports 264 spaced about the circumferential direction C and in fluid communication with primary burner chamber 230 via annular opening 262. More specifically, primary flame ports 264 are defined between top portion 202 and bottom portion 204 of upper housing 200. In this manner, primary flame ports 264 are positioned below boost flame ports 210 along the axial direction V.

One skilled in the art will appreciate that in addition to the configurations of gas burner assembly 150 described herein, alternative configurations of gas burner assembly 150 are possible and within the scope of the present subject matter. For example, the size, positioning, and configuration of bottom housing 154, center body 158, and upper housing 200 may vary, the various fuel and air mixing chambers may be positioned differently, and other mixing features or configurations may be used. It should be appreciated that still other configurations are possible and within the scope of the present subject matter.

Referring now to FIG. 11, a schematic view of gas burner assembly 150 and a gaseous fuel supply circuit 270 will be described. Although new reference numerals may be used herein to describe the schematic fuel supply circuit 270, it should be appreciated that some or all of these components may be the same or similar components as described with respect to FIGS. 1 through 10. In general, gaseous fuel supply circuit 270 is configured for selectively supplying gaseous fuel such as propane or natural gas to a primary burner (which will be identified here as numeral 272 for simplicity) and a boost burner (which will be identified here as numeral 274 for simplicity) to regulate the amount of heat generated by the respective stages. In particular, gaseous fuel supply circuit 270 is configured for selectively supplying gaseous fuel to only primary burner 272 or to both primary and boost burners 272, 274 depending upon the desired output of gas burner assembly 150 selected by a user of gas burner assembly 150. Thus, primary burner 272 is separate or independent from boost burner 274, e.g., such that primary burner 272 is not in fluid communication with boost burner 274 within gas burner assembly 150. In such manner, gaseous fuel within gas burner assembly 150 does not flow between primary and boost burners 272, 274.

As shown in FIG. 11, gaseous fuel supply circuit 270 includes a supply line 276 that may be coupled to a pressurized gaseous fuel source 278, such as a natural gas supply line or a propane tank. In this manner, gaseous fuel (e.g., natural gas or propane) is flowable from the pressurized gaseous fuel source 278 into supply line 276. Gaseous fuel supply circuit 270 further includes a dual-outlet control valve 280 (which may be equivalent to fuel control valve 120) operably coupled to supply line 276 for selectively directing a metered amount of fuel to primary burner 272 and boost burner 274. More specifically, dual-outlet control valve 280 includes an inlet 282 fluidly coupled with supply line 276, a first outlet or primary outlet 284 fluidly coupled with a primary fuel line 286 and extending to first orifice 288, and a second outlet or boost outlet 290 fluidly coupled with a boost fuel line 292 and extending to second orifice 294. Thus, supply line 276 is positioned upstream of primary and boost fuel lines 286, 292 relative to a flow of gaseous fuel from fuel source 278, and primary and boost fuel lines 286, 292 may be split off of supply line 276.

In operation, gaseous fuel from the supply line 276 may flow to primary and boost fuel lines 286, 292. From primary fuel line 286, the gaseous fuel may flow to first orifice 288. In this regard, first orifice 288 is positioned for directing gaseous fuel into gas burner assembly 150, or more particularly into primary burner 272. Second orifice 294 is also positioned for directing gaseous fuel into gas burner assembly 150, or more particularly into boost burner 274. Thus, primary and boost fuel lines 286, 292 may separately supply the gaseous fuel from supply line 276 to primary and boost burners 272, 274.

Dual-outlet control valve 280 is coupled to supply line 276, e.g., upstream of primary and boost fuel lines 286, 292. According to the illustrated embodiment, a solenoid valve 296 is coupled to boost fuel line 292, e.g., upstream of second orifice 294. Thus, solenoid valve 296 may be positioned between supply line 276 and second orifice 294. Dual-outlet control valve 280 is selectively adjustable to regulate gaseous fuel flow through supply line 276 to primary and boost fuel lines 286, 292. Solenoid valve 296 is selectively adjustable to allow gaseous fuel flow through boost fuel line 292 to second orifice 294. For example, according to an exemplary embodiment, solenoid valve 296 is operably coupled to a forced air supply source, such as a fan 298, and is configured to shut off the flow of fuel in boost fuel line 292 in the event of a fan failure. In addition, solenoid valve 296 may be normally closed and openable in response to dual-outlet control valve 280 shifting to the boost position and to fan 298 activating, as described in more detail below. Thus, dual-outlet control valve 280 and solenoid valve 296 cooperate to regulate gaseous fuel flow to primary and boost burners 272, 274.

As illustrated, dual-outlet control valve 280 is coupled to control knob 108 to allow a user to regulate the flows of fuel to primary burner 272 and boost burner 274. Similarly, fan 298 may be either directly controlled by control knob 108 or may be controlled based on the amount of fuel supplied to obtain the desired air/fuel ratio for combustion. A user may rotate control knob 108 to adjust fuel flow through supply line 276 with dual-outlet control valve 280. In particular, gas burner assembly 150 may have a respective heat output at each position of control knob 108. It will be understood that while described herein in the context of the positions of control knob 108, the description also corresponds to the positions and/or configurations of dual-outlet control valve 280 for regulating operation of gas burner assembly 150.

Referring now also to FIGS. 12 and 13, an operational schematic of a gas burner assembly operating using a fuel supply circuit will be described in more detail. For example, the gas burner assembly may be gas burner assembly 150 or any other gas burner and the fuel supply circuit may be fuel supply circuit 270 or have any other suitable configuration. The example operations described in FIGS. 12 and 13 are only examples used to assist in explaining aspects of the present subject matter. The scope of the present subject matter is not intended to be limited to these exemplary embodiments.

As illustrated, when control knob 108 is in the off position, dual-outlet control valve 280 blocks gaseous fuel flow through supply line 276 to primary and boost fuel lines 286, 292. Thus, gas burner assembly 150 is not supplied with gaseous fuel from gaseous fuel supply circuit 270 when control knob 108 is in the off position. Conversely, when control knob 108 is rotated to the lite position or otherwise turned on, dual-outlet control valve 280 is opened such that gaseous fuel is supplied through primary fuel line 286 to primary burner 272 only. This fuel is ignited in primary burner 272, e.g., via a spark electrode (not shown).

As fuel is being supplied to primary burner 272, gas burner assembly 150 may continuously monitor whether primary burner 272 is actually ignited. In this manner, dangerous conditions may be avoided, e.g., such as when a flame goes out but fuel is still flowing out of primary burner 272. In this regard, a flame sensor may be used to sense the presence of a flame. For instance, although any suitable flame detection sensor may be used, gas burner assembly 150 and controller 110 may include a flame rectification circuit incorporating an igniter probe (e.g., such as a spark electrode). As would be understood by one of ordinary skill in the art, a flame (e.g., at primary flame ports 264) may act as a relatively weak rectifier and alter the flow of electrons and thereby the voltage of an alternating current through the igniter probe, which acts as a flame rectification probe. In this manner, the flame rectification probe (e.g., igniter probe) may gather information regarding the rectifying effect caused by a flame generated at the burner to detect the presence of a flame.

As control knob 108 is progressively rotated into a boost position, dual-outlet control valve 280 permits gaseous fuel flow through supply line 276 to primary and boost fuel lines 286, 292. Thus, primary burner 272 is supplied with gaseous fuel from gaseous fuel supply circuit 270 when control knob 108 is in the boost position. According to one embodiment, primary burner 272 remains ignited any time boost burner 274 is on and may thus serve as an ignition source for boost burner 274. In addition, according to one exemplary embodiment, primary burner 272 may be limited to a low flow rate during the boost mode such that the flames from primary burner 272 do not impede oxygen from reaching boost burner 274 and facilitating improved combustion.

Notably, when control knob 108 is in the boost position, fan 298 is energized. However, because fan 298 takes a short amount of time to ramp up to its rated speed, the desired air flow rate will consequently be initially lower than desired. Thus, if solenoid valve 296 were opened simultaneously, the instantaneous fuel-air mixture would be fuel-rich. To prevent this, according to one exemplary embodiment, a delay is implemented prior to energizing or opening solenoid valve 296 to permit fuel to flow.

In addition, referring now to FIG. 13, when control knob 108 is turned on and gas burner assembly 150 is operating at steady state, boost burner chamber 206 is filled with fuel-air mixture. Thus, when control knob 108 is turned off, if solenoid valve 296 and fan 298 are both simultaneously stopped, a fuel-air mixture remaining within boost burner chamber 206 will burn off as long reaching flames. To prevent this, when control knob 108 is turned off, gas flow to primary burner 272 and boost burner 274 is stopped, e.g., using dual-outlet control valve 280 and closing solenoid valve 296. However, a purge delay is implemented before turning fan 298 off, such that fan 298 urges the residual fuel-air mixture out of boost burner chamber 206 quickly and safely.

Now that the construction and configuration of gas burner assembly 150, fuel supply circuit 270, and operating schematics according to exemplary embodiments of the present subject matter have been presented, an exemplary method 300 for operating gas burner assembly 150 according to an exemplary embodiment of the present subject matter is provided. In this regard, for example, controller 110 may be operably coupled to solenoid valve 296, the forced air supply, e.g., fan 298, and other components of gas burner assembly 150 or cooktop appliance 100 to implement method 300. Method 300 can be used to operate gas burner assembly 150 or any other suitable gas burner. It should be appreciated that the exemplary method 300 is discussed herein only to describe exemplary aspects of the present subject matter, and is not intended to be limiting.

Referring now to FIG. 14, method 300 includes, at step 310, receiving a command to ignite the boost burner. For example, the command to ignite the boost burner may be received from a control knob, the control panel, or any other suitable user command interface. Method 200 also includes, at step 320, determining that the primary burner is ignited. As discussed briefly above, this determination may be made by the control of the cooktop appliance, for example, using a flame sensor or a flame rectification method.

At step 330, method 300 includes activating the boost burner after determining that the primary burner is ignited. Notably, by only activating the boost burner after determining that the primary burner is ignited, undesirable operating conditions may be avoided. Specifically, if the boost burner is supplied with flows of air and fuel prior to ignition of the primary burner, the mixture will flow into the room unignited. This is because the boost burner may not have a dedicated spark electrode or other ignition source and relies on the primary burner for ignition.

If the command to ignite the boost burner is received, and the controller determines that the primary burner is not ignited, method 300 may further include a step for energizing a spark electrode or another ignition source to ignite the primary burner. If ignition fails, controller may be configured for shutting off the dual-outlet control valve and the solenoid valve to prevent potentially hazardous conditions.

According to still another embodiment, activating the boost burner at step 330 may incorporate a delay after energizing the fan and before opening the solenoid valve. For example, activating the boost burner may include activating the fan to urge the flow of air to the boost burner chamber. After activating the fan, a time delay may be implemented before opening the solenoid valve. In this regard, the solenoid valve will permit the flow of boost fuel to the boost burner chamber after an ignition delay period that is measured from the activation of the forced air supply source. As discussed briefly above, such an ignition delay prevents the formation of a fuel rich mixture within the boost burner chamber.

The ignition delay period may be selected by a user, set by manufacturer, or programmed into the controller in any other manner. The ignition delay period may generally be selected as the amount of time necessary for the forced air supply source, e.g., the fan, to reach a rated or steady state flow rate. According to one exemplary embodiment, the ignition delay period is approximately one second. According to still another embodiment, the ignition delay period may be determined by the controller based on current operating conditions of the gas burner assembly. For example, the controller could measure the flow rate being urged by the fan to make a determination as to when fuel should be supplied through the solenoid valve.

As explained above, steps 310 through 330 relate to the ignition process of the boost burner. However, the controller may also be programmed to regulate the shutdown or shut off of the boost burner. In this regard, for example, step 340 includes receiving a command to turn off the boost burner. Similar to step 310 above, the command to turn off the boost burner may be received from the user in any suitable manner, such as via a control knob.

Method 300 further includes, at step 350, closing the solenoid valve to stop the flow of boost fuel to the boost burner chamber. At step 360, method 300 includes deactivating the forced air supply source to stop the flow of air to the boost burner chamber after a purge delay period measured from the close of the solenoid valve. In other words, steps 340 through 360 operate to close solenoid valve prior to deactivating the fan. In this manner, the flow of fuel ceases while the flow of air continues in order purge any residual fuel mixture within the boost burner chamber prior to shutting off the fan.

In general, the purge delay period is the amount of time necessary for forced air supply source, e.g., the fan, to discharge substantially all of the boost fuel mixture from the boost burner chamber. For example, the purge delay period according to one exemplary embodiment may be about two seconds. However, according to alternative embodiments, the purge delay period may be determined or calculated by the controller based on the volume of the boost burner chamber, the resistance to flow of the fuel passageways, the fan speed, etc.

FIG. 14 depicts steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that the steps of any of the methods discussed herein can be adapted, rearranged, expanded, omitted, or modified in various ways without deviating from the scope of the present disclosure. Moreover, although aspects of method 300 are explained using gas burner assembly 150 as an example, it should be appreciated that these methods may be applied to manufacture any suitable gas burners.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A gas burner assembly for a cooktop appliance, the gas burner assembly comprising: a primary burner comprising a plurality of primary flame ports in fluid communication with a primary burner chamber for receiving a flow of primary fuel; a boost burner comprising a plurality of boost burner ports in fluid communication with a boost burner chamber for receiving a flow of boost fuel; a solenoid valve for regulating the flow of boost fuel to the boost burner chamber; a forced air supply source for selectively urging a flow of air into the boost burner chamber; and a controller operably coupled to the solenoid valve and the forced air supply, the controller being configured for: receiving a command to ignite the boost burner; determining that the primary burner is ignited; and activating the boost burner after determining that the primary burner is ignited.
 2. The gas burner assembly of claim 1, wherein activating the boost burner comprises: activating the forced air supply source to urge the flow of air to the boost burner chamber; and opening the solenoid valve to permit the flow of boost fuel to the boost burner chamber after an ignition delay period measured from the activation of the forced air supply source.
 3. The gas burner assembly of claim 1, wherein the ignition delay period is the amount of time necessary for the forced air supply source to reach a rated flow rate.
 4. The gas burner assembly of claim 1, wherein the ignition delay period is approximately one second.
 5. The gas burner assembly of claim 1, wherein determining that the primary burner is ignited comprises sensing a flame presence through a spark electrode using flame rectification.
 6. The gas burner assembly of claim 1, further comprising energizing a spark electrode if the primary burner is not ignited when the command to ignite the boost burner is received.
 7. The gas burner assembly of claim 1, wherein the controller is further configured for: receiving a command to turn off the boost burner; closing the solenoid valve to stop the flow of boost fuel to the boost burner chamber; and deactivating the forced air supply source to stop the flow of air to the boost burner chamber after a purge delay period measured from the closing of the solenoid valve.
 8. The gas burner assembly of claim 7, wherein the purge delay period is the amount of time necessary for the forced air supply source to discharge substantially all of the boost fuel within the boost burner chamber.
 9. The gas burner assembly of claim 7, wherein the purge delay period is approximately two seconds.
 10. The gas burner assembly of claim 1, wherein the plurality of boost burner ports is positioned concentric with the plurality of primary flame ports.
 11. The gas burner assembly of claim 1, wherein the plurality of boost burner ports is positioned below the plurality of primary flame ports.
 12. The gas burner assembly of claim 1, wherein the primary burner is normally aspirated.
 13. The gas burner assembly of claim 1, further comprising: a dual-outlet control valve including an inlet, a primary outlet, and a boost outlet; a supply line providing fluid communication between a fuel supply source and the inlet of the dual-outlet control valve; a primary fuel line providing fluid communication between the primary outlet and the primary fuel chamber; and a boost fuel line providing fluid communication between the boost outlet and the boost fuel chamber, the dual-outlet control valve being configured for regulating gaseous fuel flow to the primary fuel line and the boost fuel line.
 14. The gas burner assembly of claim 1, comprising a control knob that is operably coupled to the controller, the command to ignite the boost burner being received when the control knob is rotated to a boost position.
 15. The gas burner assembly of claim 1, wherein the forced air supply source is a fan or an air compressor.
 16. A method for operating a gas burner assembly, the gas burner assembly including a primary burner positioned concentrically below a boost burner, a solenoid valve for regulating a flow of boost fuel to a boost burner chamber, and a forced air supply source for selectively urging a flow of air into the boost burner chamber, the method comprising: receiving a command to ignite the boost burner; determining that the primary burner is ignited; and activating the boost burner after determining that the primary burner is ignited.
 17. The method of claim 16, wherein activating the boost burner comprises: activating the forced air supply source to urge the flow of air to the boost burner chamber; and opening the solenoid valve to permit the flow of boost fuel to the boost burner chamber after an ignition delay period measured from the activation of the forced air supply source.
 18. The method of claim 17, wherein the ignition delay period is the amount of time necessary for the forced air supply source to reach a rated flow rate.
 19. The method of claim 16, further comprising: receiving a command to turn off the boost burner; closing the solenoid valve to stop the flow of boost fuel to the boost burner chamber; and deactivating the forced air supply source to stop the flow of air to the boost burner chamber after a purge delay period measured from the closing of the solenoid valve.
 20. The method of claim 19, wherein the purge delay period is the amount of time necessary for the forced air supply source to discharge substantially all of the boost fuel within the boost burner chamber. 